Effects of biological, economic and management factors on tuna and billfish stock status

Commercial tunas and billfishes (swordfish, marlins and sailfish) provide considerable catches and income in both developed and developing countries. These stocks vary in status from lightly exploited to rebuilding to severely depleted. Previous studies suggested that this variability could result from differences in life-history characteristics and economic incentives, but differences in exploitation histories and management measures also have a strong effect on current stock status. Although the status (biomass and fishing mortality rate) of major tuna and billfish stocks is well documented, the effect of these diverse factors on current stock status and the effect of management measures in rebuilding stocks have not been analysed at the global level. Here, we show that, particularly for tunas, stocks were more depleted if they had high commercial value, were long-lived species, had small pre-fishing biomass and were subject to intense fishing pressure for a long time. In addition, implementing and enforcing total allowable catches (TACs) had the strongest positive influence on rebuilding overfished tuna and billfish stocks. Other control rules such as minimum size regulations or seasonal closures were also important in reducing fishing pressure, but stocks under TAC implementations showed the fastest increase of biomass. Lessons learned from this study can be applied in managing large industrial fisheries around the world. In particular, tuna regional fisheries management organizations should consider the relative effectiveness of management measures observed in this study for rebuilding depleted large pelagic stocks.

Keyword(s)

Fisheries management, marine conservation, stock assessment, stock status, tuna fisheries

Full Text

FilePagesSizeAccess
Publisher's official version
211 Mo
Supporting Information
12744 Ko
Author's final draft
411 Mo
How to cite
Pons Maite, Branch Trevor A., Melnychuk Michael C., Jensen Olaf P., Brodziak Jon, Fromentin Jean-Marc, Harley Shelton J., Haynie Alan C., Kell Laurie T., Maunder Mark N., Parma Ana M., Restrepo Victor R., Sharma Rishi, Ahrens Robert, Hilborn Ray (2017). Effects of biological, economic and management factors on tuna and billfish stock status. Fish And Fisheries. 18 (1). 1-21. https://doi.org/10.1111/faf.12163, https://archimer.ifremer.fr/doc/00333/44383/

Copy this text